block/blk-sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Functions related to sysfs handling
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/slab.h>
   7 #include <linux/module.h>
   8 #include <linux/bio.h>
   9 #include <linux/blkdev.h>
  10 #include <linux/backing-dev.h>
  11 #include <linux/blktrace_api.h>
  12 #include <linux/blk-mq.h>
  13 #include <linux/blk-cgroup.h>
  14
  15 #include "blk.h"
  16 #include "blk-mq.h"
  17 #include "blk-mq-debugfs.h"
  18 #include "blk-wbt.h"
  19
  20 struct queue_sysfs_entry {
  21         struct attribute attr;
  22         ssize_t (*show)(struct request_queue *, char *);
  23         ssize_t (*store)(struct request_queue *, const char *, size_t);
  24 };
  25
  26 static ssize_t
  27 queue_var_show(unsigned long var, char *page)
  28 {
  29         return sprintf(page, "%lu\n", var);
  30 }
  31
  32 static ssize_t
  33 queue_var_store(unsigned long *var, const char *page, size_t count)
  34 {
  35         int err;
  36         unsigned long v;
  37
  38         err = kstrtoul(page, 10, &v);
  39         if (err || v > UINT_MAX)
  40                 return -EINVAL;
  41
  42         *var = v;
  43
  44         return count;
  45 }
  46
  47 static ssize_t queue_var_store64(s64 *var, const char *page)
  48 {
  49         int err;
  50         s64 v;
  51
  52         err = kstrtos64(page, 10, &v);
  53         if (err < 0)
  54                 return err;
  55
  56         *var = v;
  57         return 0;
  58 }
  59
  60 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  61 {
  62         return queue_var_show(q->nr_requests, (page));
  63 }
  64
  65 static ssize_t
  66 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  67 {
  68         unsigned long nr;
  69         int ret, err;
  70
  71         if (!q->request_fn && !q->mq_ops)
  72                 return -EINVAL;
  73
  74         ret = queue_var_store(&nr, page, count);
  75         if (ret < 0)
  76                 return ret;
  77
  78         if (nr < BLKDEV_MIN_RQ)
  79                 nr = BLKDEV_MIN_RQ;
  80
  81         if (q->request_fn)
  82                 err = blk_update_nr_requests(q, nr);
  83         else
  84                 err = blk_mq_update_nr_requests(q, nr);
  85
  86         if (err)
  87                 return err;
  88
  89         return ret;
  90 }
  91
  92 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  93 {
  94         unsigned long ra_kb = q->backing_dev_info->ra_pages <<
  95                                         (PAGE_SHIFT - 10);
  96
  97         return queue_var_show(ra_kb, (page));
  98 }
  99
 100 static ssize_t
 101 queue_ra_store(struct request_queue *q, const char *page, size_t count)
 102 {
 103         unsigned long ra_kb;
 104         ssize_t ret = queue_var_store(&ra_kb, page, count);
 105
 106         if (ret < 0)
 107                 return ret;
 108
 109         q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 110
 111         return ret;
 112 }
 113
 114 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 115 {
 116         int max_sectors_kb = queue_max_sectors(q) >> 1;
 117
 118         return queue_var_show(max_sectors_kb, (page));
 119 }
 120
 121 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 122 {
 123         return queue_var_show(queue_max_segments(q), (page));
 124 }
 125
 126 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
 127                 char *page)
 128 {
 129         return queue_var_show(queue_max_discard_segments(q), (page));
 130 }
 131
 132 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 133 {
 134         return queue_var_show(q->limits.max_integrity_segments, (page));
 135 }
 136
 137 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 138 {
 139         if (blk_queue_cluster(q))
 140                 return queue_var_show(queue_max_segment_size(q), (page));
 141
 142         return queue_var_show(PAGE_SIZE, (page));
 143 }
 144
 145 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 146 {
 147         return queue_var_show(queue_logical_block_size(q), page);
 148 }
 149
 150 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 151 {
 152         return queue_var_show(queue_physical_block_size(q), page);
 153 }
 154
 155 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 156 {
 157         return queue_var_show(q->limits.chunk_sectors, page);
 158 }
 159
 160 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 161 {
 162         return queue_var_show(queue_io_min(q), page);
 163 }
 164
 165 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 166 {
 167         return queue_var_show(queue_io_opt(q), page);
 168 }
 169
 170 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 171 {
 172         return queue_var_show(q->limits.discard_granularity, page);
 173 }
 174
 175 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 176 {
 177
 178         return sprintf(page, "%llu\n",
 179                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 180 }
 181
 182 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 183 {
 184         return sprintf(page, "%llu\n",
 185                        (unsigned long long)q->limits.max_discard_sectors << 9);
 186 }
 187
 188 static ssize_t queue_discard_max_store(struct request_queue *q,
 189                                        const char *page, size_t count)
 190 {
 191         unsigned long max_discard;
 192         ssize_t ret = queue_var_store(&max_discard, page, count);
 193
 194         if (ret < 0)
 195                 return ret;
 196
 197         if (max_discard & (q->limits.discard_granularity - 1))
 198                 return -EINVAL;
 199
 200         max_discard >>= 9;
 201         if (max_discard > UINT_MAX)
 202                 return -EINVAL;
 203
 204         if (max_discard > q->limits.max_hw_discard_sectors)
 205                 max_discard = q->limits.max_hw_discard_sectors;
 206
 207         q->limits.max_discard_sectors = max_discard;
 208         return ret;
 209 }
 210
 211 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 212 {
 213         return queue_var_show(0, page);
 214 }
 215
 216 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 217 {
 218         return sprintf(page, "%llu\n",
 219                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 220 }
 221
 222 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 223 {
 224         return sprintf(page, "%llu\n",
 225                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 226 }
 227
 228 static ssize_t
 229 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 230 {
 231         unsigned long max_sectors_kb,
 232                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 233                         page_kb = 1 << (PAGE_SHIFT - 10);
 234         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 235
 236         if (ret < 0)
 237                 return ret;
 238
 239         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 240                                          q->limits.max_dev_sectors >> 1);
 241
 242         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 243                 return -EINVAL;
 244
 245         spin_lock_irq(q->queue_lock);
 246         q->limits.max_sectors = max_sectors_kb << 1;
 247         q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 248         spin_unlock_irq(q->queue_lock);
 249
 250         return ret;
 251 }
 252
 253 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 254 {
 255         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 256
 257         return queue_var_show(max_hw_sectors_kb, (page));
 258 }
 259
 260 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 261 static ssize_t                                                          \
 262 queue_show_##name(struct request_queue *q, char *page)                  \
 263 {                                                                       \
 264         int bit;                                                        \
 265         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 266         return queue_var_show(neg ? !bit : bit, page);                  \
 267 }                                                                       \
 268 static ssize_t                                                          \
 269 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 270 {                                                                       \
 271         unsigned long val;                                              \
 272         ssize_t ret;                                                    \
 273         ret = queue_var_store(&val, page, count);                       \
 274         if (ret < 0)                                                    \
 275                  return ret;                                            \
 276         if (neg)                                                        \
 277                 val = !val;                                             \
 278                                                                         \
 279         if (val)                                                        \
 280                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
 281         else                                                            \
 282                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
 283         return ret;                                                     \
 284 }
 285
 286 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 287 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 288 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 289 #undef QUEUE_SYSFS_BIT_FNS
 290
 291 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 292 {
 293         switch (blk_queue_zoned_model(q)) {
 294         case BLK_ZONED_HA:
 295                 return sprintf(page, "host-aware\n");
 296         case BLK_ZONED_HM:
 297                 return sprintf(page, "host-managed\n");
 298         default:
 299                 return sprintf(page, "none\n");
 300         }
 301 }
 302
 303 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 304 {
 305         return queue_var_show((blk_queue_nomerges(q) << 1) |
 306                                blk_queue_noxmerges(q), page);
 307 }
 308
 309 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 310                                     size_t count)
 311 {
 312         unsigned long nm;
 313         ssize_t ret = queue_var_store(&nm, page, count);
 314
 315         if (ret < 0)
 316                 return ret;
 317
 318         spin_lock_irq(q->queue_lock);
 319         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 320         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 321         if (nm == 2)
 322                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 323         else if (nm)
 324                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 325         spin_unlock_irq(q->queue_lock);
 326
 327         return ret;
 328 }
 329
 330 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 331 {
 332         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 333         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 334
 335         return queue_var_show(set << force, page);
 336 }
 337
 338 static ssize_t
 339 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 340 {
 341         ssize_t ret = -EINVAL;
 342 #ifdef CONFIG_SMP
 343         unsigned long val;
 344
 345         ret = queue_var_store(&val, page, count);
 346         if (ret < 0)
 347                 return ret;
 348
 349         spin_lock_irq(q->queue_lock);
 350         if (val == 2) {
 351                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 352                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 353         } else if (val == 1) {
 354                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 355                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 356         } else if (val == 0) {
 357                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 358                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 359         }
 360         spin_unlock_irq(q->queue_lock);
 361 #endif
 362         return ret;
 363 }
 364
 365 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 366 {
 367         int val;
 368
 369         if (q->poll_nsec == -1)
 370                 val = -1;
 371         else
 372                 val = q->poll_nsec / 1000;
 373
 374         return sprintf(page, "%d\n", val);
 375 }
 376
 377 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 378                                 size_t count)
 379 {
 380         int err, val;
 381
 382         if (!q->mq_ops || !q->mq_ops->poll)
 383                 return -EINVAL;
 384
 385         err = kstrtoint(page, 10, &val);
 386         if (err < 0)
 387                 return err;
 388
 389         if (val == -1)
 390                 q->poll_nsec = -1;
 391         else
 392                 q->poll_nsec = val * 1000;
 393
 394         return count;
 395 }
 396
 397 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 398 {
 399         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 400 }
 401
 402 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 403                                 size_t count)
 404 {
 405         unsigned long poll_on;
 406         ssize_t ret;
 407
 408         if (!q->mq_ops || !q->mq_ops->poll)
 409                 return -EINVAL;
 410
 411         ret = queue_var_store(&poll_on, page, count);
 412         if (ret < 0)
 413                 return ret;
 414
 415         if (poll_on)
 416                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
 417         else
 418                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
 419
 420         return ret;
 421 }
 422
 423 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 424 {
 425         if (!q->rq_wb)
 426                 return -EINVAL;
 427
 428         return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000));
 429 }
 430
 431 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 432                                   size_t count)
 433 {
 434         struct rq_wb *rwb;
 435         ssize_t ret;
 436         s64 val;
 437
 438         ret = queue_var_store64(&val, page);
 439         if (ret < 0)
 440                 return ret;
 441         if (val < -1)
 442                 return -EINVAL;
 443
 444         rwb = q->rq_wb;
 445         if (!rwb) {
 446                 ret = wbt_init(q);
 447                 if (ret)
 448                         return ret;
 449         }
 450
 451         rwb = q->rq_wb;
 452         if (val == -1)
 453                 rwb->min_lat_nsec = wbt_default_latency_nsec(q);
 454         else if (val >= 0)
 455                 rwb->min_lat_nsec = val * 1000ULL;
 456
 457         if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
 458                 rwb->enable_state = WBT_STATE_ON_MANUAL;
 459
 460         wbt_update_limits(rwb);
 461         return count;
 462 }
 463
 464 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 465 {
 466         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 467                 return sprintf(page, "write back\n");
 468
 469         return sprintf(page, "write through\n");
 470 }
 471
 472 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 473                               size_t count)
 474 {
 475         int set = -1;
 476
 477         if (!strncmp(page, "write back", 10))
 478                 set = 1;
 479         else if (!strncmp(page, "write through", 13) ||
 480                  !strncmp(page, "none", 4))
 481                 set = 0;
 482
 483         if (set == -1)
 484                 return -EINVAL;
 485
 486         if (set)
 487                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 488         else
 489                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 490
 491         return count;
 492 }
 493
 494 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 495 {
 496         return queue_var_show(blk_queue_dax(q), page);
 497 }
 498
 499 static struct queue_sysfs_entry queue_requests_entry = {
 500         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 501         .show = queue_requests_show,
 502         .store = queue_requests_store,
 503 };
 504
 505 static struct queue_sysfs_entry queue_ra_entry = {
 506         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 507         .show = queue_ra_show,
 508         .store = queue_ra_store,
 509 };
 510
 511 static struct queue_sysfs_entry queue_max_sectors_entry = {
 512         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 513         .show = queue_max_sectors_show,
 514         .store = queue_max_sectors_store,
 515 };
 516
 517 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 518         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 519         .show = queue_max_hw_sectors_show,
 520 };
 521
 522 static struct queue_sysfs_entry queue_max_segments_entry = {
 523         .attr = {.name = "max_segments", .mode = S_IRUGO },
 524         .show = queue_max_segments_show,
 525 };
 526
 527 static struct queue_sysfs_entry queue_max_discard_segments_entry = {
 528         .attr = {.name = "max_discard_segments", .mode = S_IRUGO },
 529         .show = queue_max_discard_segments_show,
 530 };
 531
 532 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 533         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 534         .show = queue_max_integrity_segments_show,
 535 };
 536
 537 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 538         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 539         .show = queue_max_segment_size_show,
 540 };
 541
 542 static struct queue_sysfs_entry queue_iosched_entry = {
 543         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 544         .show = elv_iosched_show,
 545         .store = elv_iosched_store,
 546 };
 547
 548 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 549         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 550         .show = queue_logical_block_size_show,
 551 };
 552
 553 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 554         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 555         .show = queue_logical_block_size_show,
 556 };
 557
 558 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 559         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 560         .show = queue_physical_block_size_show,
 561 };
 562
 563 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
 564         .attr = {.name = "chunk_sectors", .mode = S_IRUGO },
 565         .show = queue_chunk_sectors_show,
 566 };
 567
 568 static struct queue_sysfs_entry queue_io_min_entry = {
 569         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 570         .show = queue_io_min_show,
 571 };
 572
 573 static struct queue_sysfs_entry queue_io_opt_entry = {
 574         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 575         .show = queue_io_opt_show,
 576 };
 577
 578 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 579         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 580         .show = queue_discard_granularity_show,
 581 };
 582
 583 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 584         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
 585         .show = queue_discard_max_hw_show,
 586 };
 587
 588 static struct queue_sysfs_entry queue_discard_max_entry = {
 589         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
 590         .show = queue_discard_max_show,
 591         .store = queue_discard_max_store,
 592 };
 593
 594 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 595         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 596         .show = queue_discard_zeroes_data_show,
 597 };
 598
 599 static struct queue_sysfs_entry queue_write_same_max_entry = {
 600         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 601         .show = queue_write_same_max_show,
 602 };
 603
 604 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
 605         .attr = {.name = "write_zeroes_max_bytes", .mode = S_IRUGO },
 606         .show = queue_write_zeroes_max_show,
 607 };
 608
 609 static struct queue_sysfs_entry queue_nonrot_entry = {
 610         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 611         .show = queue_show_nonrot,
 612         .store = queue_store_nonrot,
 613 };
 614
 615 static struct queue_sysfs_entry queue_zoned_entry = {
 616         .attr = {.name = "zoned", .mode = S_IRUGO },
 617         .show = queue_zoned_show,
 618 };
 619
 620 static struct queue_sysfs_entry queue_nomerges_entry = {
 621         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 622         .show = queue_nomerges_show,
 623         .store = queue_nomerges_store,
 624 };
 625
 626 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 627         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 628         .show = queue_rq_affinity_show,
 629         .store = queue_rq_affinity_store,
 630 };
 631
 632 static struct queue_sysfs_entry queue_iostats_entry = {
 633         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 634         .show = queue_show_iostats,
 635         .store = queue_store_iostats,
 636 };
 637
 638 static struct queue_sysfs_entry queue_random_entry = {
 639         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 640         .show = queue_show_random,
 641         .store = queue_store_random,
 642 };
 643
 644 static struct queue_sysfs_entry queue_poll_entry = {
 645         .attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
 646         .show = queue_poll_show,
 647         .store = queue_poll_store,
 648 };
 649
 650 static struct queue_sysfs_entry queue_poll_delay_entry = {
 651         .attr = {.name = "io_poll_delay", .mode = S_IRUGO | S_IWUSR },
 652         .show = queue_poll_delay_show,
 653         .store = queue_poll_delay_store,
 654 };
 655
 656 static struct queue_sysfs_entry queue_wc_entry = {
 657         .attr = {.name = "write_cache", .mode = S_IRUGO | S_IWUSR },
 658         .show = queue_wc_show,
 659         .store = queue_wc_store,
 660 };
 661
 662 static struct queue_sysfs_entry queue_dax_entry = {
 663         .attr = {.name = "dax", .mode = S_IRUGO },
 664         .show = queue_dax_show,
 665 };
 666
 667 static struct queue_sysfs_entry queue_wb_lat_entry = {
 668         .attr = {.name = "wbt_lat_usec", .mode = S_IRUGO | S_IWUSR },
 669         .show = queue_wb_lat_show,
 670         .store = queue_wb_lat_store,
 671 };
 672
 673 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 674 static struct queue_sysfs_entry throtl_sample_time_entry = {
 675         .attr = {.name = "throttle_sample_time", .mode = S_IRUGO | S_IWUSR },
 676         .show = blk_throtl_sample_time_show,
 677         .store = blk_throtl_sample_time_store,
 678 };
 679 #endif
 680
 681 static struct attribute *default_attrs[] = {
 682         &queue_requests_entry.attr,
 683         &queue_ra_entry.attr,
 684         &queue_max_hw_sectors_entry.attr,
 685         &queue_max_sectors_entry.attr,
 686         &queue_max_segments_entry.attr,
 687         &queue_max_discard_segments_entry.attr,
 688         &queue_max_integrity_segments_entry.attr,
 689         &queue_max_segment_size_entry.attr,
 690         &queue_iosched_entry.attr,
 691         &queue_hw_sector_size_entry.attr,
 692         &queue_logical_block_size_entry.attr,
 693         &queue_physical_block_size_entry.attr,
 694         &queue_chunk_sectors_entry.attr,
 695         &queue_io_min_entry.attr,
 696         &queue_io_opt_entry.attr,
 697         &queue_discard_granularity_entry.attr,
 698         &queue_discard_max_entry.attr,
 699         &queue_discard_max_hw_entry.attr,
 700         &queue_discard_zeroes_data_entry.attr,
 701         &queue_write_same_max_entry.attr,
 702         &queue_write_zeroes_max_entry.attr,
 703         &queue_nonrot_entry.attr,
 704         &queue_zoned_entry.attr,
 705         &queue_nomerges_entry.attr,
 706         &queue_rq_affinity_entry.attr,
 707         &queue_iostats_entry.attr,
 708         &queue_random_entry.attr,
 709         &queue_poll_entry.attr,
 710         &queue_wc_entry.attr,
 711         &queue_dax_entry.attr,
 712         &queue_wb_lat_entry.attr,
 713         &queue_poll_delay_entry.attr,
 714 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 715         &throtl_sample_time_entry.attr,
 716 #endif
 717         NULL,
 718 };
 719
 720 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 721
 722 static ssize_t
 723 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 724 {
 725         struct queue_sysfs_entry *entry = to_queue(attr);
 726         struct request_queue *q =
 727                 container_of(kobj, struct request_queue, kobj);
 728         ssize_t res;
 729
 730         if (!entry->show)
 731                 return -EIO;
 732         mutex_lock(&q->sysfs_lock);
 733         if (blk_queue_dying(q)) {
 734                 mutex_unlock(&q->sysfs_lock);
 735                 return -ENOENT;
 736         }
 737         res = entry->show(q, page);
 738         mutex_unlock(&q->sysfs_lock);
 739         return res;
 740 }
 741
 742 static ssize_t
 743 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 744                     const char *page, size_t length)
 745 {
 746         struct queue_sysfs_entry *entry = to_queue(attr);
 747         struct request_queue *q;
 748         ssize_t res;
 749
 750         if (!entry->store)
 751                 return -EIO;
 752
 753         q = container_of(kobj, struct request_queue, kobj);
 754         mutex_lock(&q->sysfs_lock);
 755         if (blk_queue_dying(q)) {
 756                 mutex_unlock(&q->sysfs_lock);
 757                 return -ENOENT;
 758         }
 759         res = entry->store(q, page, length);
 760         mutex_unlock(&q->sysfs_lock);
 761         return res;
 762 }
 763
 764 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 765 {
 766         struct request_queue *q = container_of(rcu_head, struct request_queue,
 767                                                rcu_head);
 768         kmem_cache_free(blk_requestq_cachep, q);
 769 }
 770
 771 /**
 772  * __blk_release_queue - release a request queue when it is no longer needed
 773  * @work: pointer to the release_work member of the request queue to be released
 774  *
 775  * Description:
 776  *     blk_release_queue is the counterpart of blk_init_queue(). It should be
 777  *     called when a request queue is being released; typically when a block
 778  *     device is being de-registered. Its primary task it to free the queue
 779  *     itself.
 780  *
 781  * Notes:
 782  *     The low level driver must have finished any outstanding requests first
 783  *     via blk_cleanup_queue().
 784  *
 785  *     Although blk_release_queue() may be called with preemption disabled,
 786  *     __blk_release_queue() may sleep.
 787  */
 788 static void __blk_release_queue(struct work_struct *work)
 789 {
 790         struct request_queue *q = container_of(work, typeof(*q), release_work);
 791
 792         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 793                 blk_stat_remove_callback(q, q->poll_cb);
 794         blk_stat_free_callback(q->poll_cb);
 795
 796         blk_free_queue_stats(q->stats);
 797
 798         blk_exit_rl(q, &q->root_rl);
 799
 800         if (q->queue_tags)
 801                 __blk_queue_free_tags(q);
 802
 803         if (!q->mq_ops) {
 804                 if (q->exit_rq_fn)
 805                         q->exit_rq_fn(q, q->fq->flush_rq);
 806                 blk_free_flush_queue(q->fq);
 807         } else {
 808                 blk_mq_release(q);
 809         }
 810
 811         blk_trace_shutdown(q);
 812
 813         if (q->mq_ops)
 814                 blk_mq_debugfs_unregister(q);
 815
 816         if (q->bio_split)
 817                 bioset_free(q->bio_split);
 818
 819         ida_simple_remove(&blk_queue_ida, q->id);
 820         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 821 }
 822
 823 static void blk_release_queue(struct kobject *kobj)
 824 {
 825         struct request_queue *q =
 826                 container_of(kobj, struct request_queue, kobj);
 827
 828         INIT_WORK(&q->release_work, __blk_release_queue);
 829         schedule_work(&q->release_work);
 830 }
 831
 832 static const struct sysfs_ops queue_sysfs_ops = {
 833         .show   = queue_attr_show,
 834         .store  = queue_attr_store,
 835 };
 836
 837 struct kobj_type blk_queue_ktype = {
 838         .sysfs_ops      = &queue_sysfs_ops,
 839         .default_attrs  = default_attrs,
 840         .release        = blk_release_queue,
 841 };
 842
 843 /**
 844  * blk_register_queue - register a block layer queue with sysfs
 845  * @disk: Disk of which the request queue should be registered with sysfs.
 846  */
 847 int blk_register_queue(struct gendisk *disk)
 848 {
 849         int ret;
 850         struct device *dev = disk_to_dev(disk);
 851         struct request_queue *q = disk->queue;
 852
 853         if (WARN_ON(!q))
 854                 return -ENXIO;
 855
 856         WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags),
 857                   "%s is registering an already registered queue\n",
 858                   kobject_name(&dev->kobj));
 859         queue_flag_set_unlocked(QUEUE_FLAG_REGISTERED, q);
 860
 861         /*
 862          * SCSI probing may synchronously create and destroy a lot of
 863          * request_queues for non-existent devices.  Shutting down a fully
 864          * functional queue takes measureable wallclock time as RCU grace
 865          * periods are involved.  To avoid excessive latency in these
 866          * cases, a request_queue starts out in a degraded mode which is
 867          * faster to shut down and is made fully functional here as
 868          * request_queues for non-existent devices never get registered.
 869          */
 870         if (!blk_queue_init_done(q)) {
 871                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 872                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 873                 blk_queue_bypass_end(q);
 874         }
 875
 876         ret = blk_trace_init_sysfs(dev);
 877         if (ret)
 878                 return ret;
 879
 880         /* Prevent changes through sysfs until registration is completed. */
 881         mutex_lock(&q->sysfs_lock);
 882
 883         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 884         if (ret < 0) {
 885                 blk_trace_remove_sysfs(dev);
 886                 goto unlock;
 887         }
 888
 889         if (q->mq_ops) {
 890                 __blk_mq_register_dev(dev, q);
 891                 blk_mq_debugfs_register(q);
 892         }
 893
 894         kobject_uevent(&q->kobj, KOBJ_ADD);
 895
 896         wbt_enable_default(q);
 897
 898         blk_throtl_register_queue(q);
 899
 900         if (q->request_fn || (q->mq_ops && q->elevator)) {
 901                 ret = elv_register_queue(q);
 902                 if (ret) {
 903                         mutex_unlock(&q->sysfs_lock);
 904                         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 905                         kobject_del(&q->kobj);
 906                         blk_trace_remove_sysfs(dev);
 907                         kobject_put(&dev->kobj);
 908                         return ret;
 909                 }
 910         }
 911         ret = 0;
 912 unlock:
 913         mutex_unlock(&q->sysfs_lock);
 914         return ret;
 915 }
 916 EXPORT_SYMBOL_GPL(blk_register_queue);
 917
 918 /**
 919  * blk_unregister_queue - counterpart of blk_register_queue()
 920  * @disk: Disk of which the request queue should be unregistered from sysfs.
 921  *
 922  * Note: the caller is responsible for guaranteeing that this function is called
 923  * after blk_register_queue() has finished.
 924  */
 925 void blk_unregister_queue(struct gendisk *disk)
 926 {
 927         struct request_queue *q = disk->queue;
 928
 929         if (WARN_ON(!q))
 930                 return;
 931
 932         /* Return early if disk->queue was never registered. */
 933         if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
 934                 return;
 935
 936         /*
 937          * Since sysfs_remove_dir() prevents adding new directory entries
 938          * before removal of existing entries starts, protect against
 939          * concurrent elv_iosched_store() calls.
 940          */
 941         mutex_lock(&q->sysfs_lock);
 942
 943         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
 944
 945         /*
 946          * Remove the sysfs attributes before unregistering the queue data
 947          * structures that can be modified through sysfs.
 948          */
 949         if (q->mq_ops)
 950                 blk_mq_unregister_dev(disk_to_dev(disk), q);
 951         mutex_unlock(&q->sysfs_lock);
 952
 953         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 954         kobject_del(&q->kobj);
 955         blk_trace_remove_sysfs(disk_to_dev(disk));
 956
 957         wbt_exit(q);
 958
 959         mutex_lock(&q->sysfs_lock);
 960         if (q->request_fn || (q->mq_ops && q->elevator))
 961                 elv_unregister_queue(q);
 962         mutex_unlock(&q->sysfs_lock);
 963
 964         kobject_put(&disk_to_dev(disk)->kobj);
 965 }